Vacuum churn



R. D. PIKE VACUUM CHURN May 13, 1941.

2 Sheets-Sheet 1 INVENTOR. W094 7%)?55.

' ATTORNEY Filed Nov. 14, 1938 May 13, 1941. R. PlKE 2,241,930

VACUUM CHURN Filed Nov. 14, 1938 2 Sheets-Sheet 2 INVENTOR. Wat Fla/fie ATTORNEY Patented May 13, 1941 iJNlTED STATE VACUUM CHURN Robert 1). Pike, Piedmont, Calif, assignor to A. W. Stitt, San Francisco, Calif.

'7 Claims.

My present invention relates to vacuum butter churns and means for introducing a partial vacuum, or creating sub-atmospheric pressure, inside the churn at will during the churning and/or butter working operation without interrupting the operation of the churn.

My invention is applied particularly to churns of the so-called internal worker type utilizing a single r011 concentric with the churn itself which works the butter in well-known fashion by kneading it between the independently rotating central roll and shelves which are fixed rigidly in the churn. My invention may be applied either to wooden churns which are mounted in an outer stationary shell in which a like vacuum is maintained to that within the churn itself, thus removing stresses due to pressure differences from the Wood of the churn, or it may be applied to a churn reinforced with metal so as to be enabled to withstand the outside pressure of the atmosphere when a vacuum prevails within the churn.

Objects of my invention comprise a means of creating a partial Vacuum within the churn and its outer casing, if such be present, without the use of mechanically operated valves, and in such I a manner as to permit of the churn being half filled with cream as is customary, without drawing the cream out under the suction of the vacuum pump.

With these and other objects in view, I refer to the drawings in which Fig. l is a longitudinal sectional view of a churn in which the Wooden staves and head of the churn are encased in metal for withstanding the pressure of the outside atmosphere and in which the present invention is embodied;

Fig. 2 is a longitudinal section of a woodenv churn mounted within an outer stationary vacuum chamber, the principal bearings on the socalled idle end of the churn being arranged outside the vacuum chamber;

Fig. 3 is an enlarged section of a portion of the churn shown in Fig. 2;

Fig. 4 is a longitudinal section of a wooden churn mounted within an outer stationary vac- 'uum chamber, the principal bearing upon which the churn rotates on its so-called idle end being within the vacuum chamber, and

Fig, 5 shows a modification of my invention as applied to a pressure sustaining churn in a manner which may be equally well applied to a nonpressure sustaining churn mounted within a vacuum vessel.

Referring first to Fig. 1, I0 is an outer steel leak-proof casing enclosing the churn proper, and

having heads H designed to withstand the outer pressure. Wooden staves l2 are set within the outer shell and wooden heads l3 set tight up against the metal heads II. This wood-lined construction is preferred, but it Will be understood that if desired the wood may be omitted and the cream may come into contact with the metal. Worker shelves i l and I5 and a central worker it are employed in a manner which is conventional for churns of this type. The worker l6 terminates in .a shaft H which is concentrically bored as at E8. Ports l9 and 20 communicate with the inner and outer ends respectively of the bore H8. The shaft ll passes through a bearing 2i in the churn head, an outside stationary bearing 22 and a stufiing box 23. At its outer end the shaft ll terminates in a hollow bearing 2s which is provided with suitable stuffing boxes 25. A pipe 2% communicates with the annular space within the bearing 24 and leads to a vacuum pump, not shown, and a pipe 21 branches from the pipe 26 for communication with a source of fluid under pressure such as air or steam or may in some instances serve as a vent to the atmosphere. Suitable valves 26 and 27* control the passage of fluid through the pipes 26 and 21 respectively. The churn itself terminates in a hollow concentric shaft 28 which rotates in and is supported by a bearing 29.

The worker .at its so-called i-dle end, where it is attached to the shaft ll, terminates in a frustum-- like recess which is preferably lined with a cup H of stainless steel or the like. Attached to the churn head concentrically with the cup 3| is the frustum-like plug 32, which is also preferably made of non-corrosive metal. A small annular space exists between the cup 3| and plug 32. The roll it is operated as will presently be described to rotate in a direction opposite to the churn itself so that any liquid in the annulus between the cup 3i and the plug 32 will, on that account, tend to be pumped out into the churn. Such pumping action may be assisted by helical vanes 33 which are preferably formed integrally with the plug 32 as shown or with the cup 3!. A number of ports 34 are provided to permit drainage or pumping back into the churn of any liquid which may tend to accumulate in the hollow space 35.

Referring to Fig. 2, a wooden churn is shown at 36 as mounted within an outer stationary airtight casing 31. The churn terminates in a hollow shaft 38 rotatably supported in a stationary bearing 39. A suitable stufiing box 31a. is provided in shell 31 to prevent leakage around the rotating shaft 38. The shaft I! and its connections are the same as those described in connection with Fig. 1. However, a port 40 is provided in theshaft l1 and together with a port M in the shaft 38 forms a communication between the source of vacuum and the space between the Wooden churn 36 and steel container 31, thus establishing equal pressure conditions on the inside and outside of the wooden churn. A drain 43 is provided in the outer casing 3! which may be used to drain off any butter, milk or other fluid which might possibly escape into the stationary casing and accumulate in the bottom thereof.

In Fig. 4 a stationary hollow cylindrical support 44 is attached to the head of the outer stationary casing 31, concentric with the churn, and

extends inwardly to provide a bearingupon-which the churn 36 rotates. The usual stuffing box is also provided to surround the shaft II. The same means is employed as is described in Fig. 2 to efiect equal conditions of pressure within the. churn. and in the space. between the churn andthe casing 31, port 4m corresponding to port 41 in Figs. 2 and'3.

In the modification of the invention illustrated in Fig. 5 of the drawings, the shaft I1 through which the Vacuumi's transmitted to the center of the. churn is adapted to be rotated at high speed through the medium of a drive pulley J8. secured'to its outer end. The working roll I6 within the churn in this form of the invention is provided with. a bearing 49 which receives the inner. end'ofthe shaft I! in a manner to permit this rotation. A' disk-like impeller 59 is secured to the. shaft l'l intermediate the end. of the worker l6 and the inner. end of. the churn, and is provided with vanes which establish a plurality of' radially extending, passages 51, which communicate' with the central bore [8 of the shaft l1. Thus the disk-like member 50 operates in themanner ofth'eim-peller'of' a centrifugal pump, and while. the radial passages establish a communication'with a' source of vacuum, the rotation of the shaft and member 50 at high speed sets up a force which prevents the entrance of solid" or liquid matter into the bore I8 of the shaft I1.

In each of the modifications of the invention described above, only one end of thechurn has been referred to; the opposite or drive end of thechurn' in each instance includes mechanism by which the'churnitself may be rotated and by which thecentral worker i6 may be rotated in an opposite direction. Any conventional mechanism-may be employed for this purpose and the mechanism presently tobe described, which is illustrated in the accompanying drawings, is typical of those which may be used in the forms of the invention shown in Figs. 1 and 5, wherein a rotatable metal, wood-lined churn is shown. The churn itself" is adapted to be rotated by a hollow shaft 55 supported in a bearing 56 and having at its outer end a drive pulley 51 to which rotary movement maybe imparted by a source of power, not shown. In order that the worker E 6 may be rotated ina direction opposite to that of the churn, there is provided a shaft 58 which passesthroughthe-hollow shaft 55 and has affixed to its outer enda drivepulley 59-. A conventional stufing box 68 isemployed at the point where the shaft 58- emerges from the hollow shaft 55.

In Figs. Z'and' 4 where the rotatable churn is constructed'of'wood andsurrounded by a spaced stationary pressure-resisting. casing 31, the drive means is similar to that described above, except that the hollow shaft 55 extends through the stationary casing 31 and is surrounded at the point where it passes through the casing with a stufiing box, as shown at 6|, which serves to prevent the entrance of atmospheric pressure into the casing during operation of the churn.

Operation of the invention is somewhat similar in each of the modifications disclosed above. The churn is filled approximately half full of cream through any conventional form of openings (not shown), through which access may be had to the interior of the churn. While the apparatus is stationary, the vacuum pipe 26 is closed by its valve 26 and the pipe 21 is open to atmosphere. The cream fills the lower half of the space 35 within the member 32' and may also flow through the hole 28 and half fill the shaft bore M. A very small amount of cream may flow into the lower part of the hollow bearing 24 and this may be drained out through a drain 4'! controlled by a valve l! as, soon as the churn has started. The starting of the churn immediately starts the described pumping action between the members 3| and- 32, or by the centrifugal impeller illustrated in Fig. 5, whereby the cream is quickly drained out ofbore l8 and pumped back into the churn proper. After starting the churn, the valve 21 is closed and vacuum gradually transmitted through the pipe 25. The vacuum should be controlled to the extent that it will not overcome the pumping action and draw cream out through the bore l8; As soon as the desired degree of vacuum has been reached there is a substantial balance of pressures and there is very little flow of gas out through the bore l8 and the aforesaid pumping action easily keeps all liquid material within the churn. Steam may, if desired, be admitted through valve 2% between operations to flush the system out, thus maintaining it in a thoroughly sanitary condition, although the vacuum itself promotes sanitation and the use of steam or other cleaning fluids is not essential.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a vacuum churn which comprises a rotatable container and a co-axially rotatable worker within the container, a hollow shaft communicating with a source of vacuum and extending into the container concentrically thereof, said worker having a recess in its end, and a member carried by the churn and entering said recess to provide a tapered annular space communicating between the interior of the churn and the hollow shaft.

2. In a vacuum churn which comprises a rotatable container and. a co-axially rotatable worker within the container, means providing an annular space between adjacent ends of the container and worker, a hollow shaft communicating with a source of vacuum and extending into the container concentrically thereof, and helical vanes in said space to effect a pumping action toward the interior of the churn.

3. In a vacuum churn which comprises a rotatable container and a co-axially rotatable worker within the container, a hollow shaft communicating with a source of vacuum and extend,- ing into the container concentrically thereof, the end of said worker and interior of the churn being. shaped to form a tapered annular space communicating'between the interior of the churn and the hollow shaft.

4. In a vacuum churn which comprises a ro- "tatable container and a co-axially rotatableworker within the container, a hollow shaft communicating with a source of vacuum and extending into the container'concentrically thereof, the end of said worker and interior of the churn being shaped to form a tapered annular space communicating between the interior of the churn and the hollow shaft, and helical vanes in said space to effect a pumping action toward the interior of the churn.

5. In a vacuum churn which comprises a rotatable container and a co-axially rotatable worker within the container, a hollow shaft communicating with a source of vacuum and extending into the container concentricallly thereof, and means forming fluid communication between the interior of the container and the hollow shaft, said means operating to pump liquids toward the interior of the container while gases are being withdrawn from the container therethrough.

6. In a vacuum churn which comprises a container rotatable within a pressure resisting casing, a hollow shaft extending through the casing and into the container co-axially therewith, said shaft being in communication with a source of vacuum and having ports communicating with the interior of the container and ports communicating with the space between the container and casing.

7. In a vacuum churn which comprises a container rotatable within apressure-resisting casing, a hollow shaft extending through the casing and into the container co-axially therewith, said shaft being in communication with a source of vacuum and having ports communicating with the interior of the container and ports communieating with the space between the container and casing, and means within the container to prevent liquids from flowing therefrom toward the source of vacuum.

ROBERT D. PlKE. 

